| Abstract: |
Lumbar spinal stenosis is defined as the narrowing of the central lumbar canal, the lateral recess, or the intervertebral foramen. Although there are many causes of spinal stenosis, this study focused on the degenerative process. Degenerative changes and narrowing can occur centrally; in the lateral recess, leading to nerve-root impingement from an overhanging hypertrophic facet joint; within the nerve-root canal (foraminal stenosis); or extraforaminally, frequently because of entrapment by osteophytes, discs, transverse processes or the sacroiliac articulation for the fifth lumbar nerve root.The clinical features of the disease are often subjective, vague, ill-described and lack substantiation on examination; therefore the history, rather than the objective findings, is the clue to reach a proper diagnosis. The typical symptoms of spinal stenosis include neurogenic claudication, back and leg pain, and mixed symptoms. Physical signs may include positive back signs, motor and sensory deficits, reflex changes and positive stretch signs. In many instances, the clinical examination may be completely normal. The pathophysiology of the symptoms is still controversial, but recent observations suggest that two-level stenosing pathology plays a significant role. Two-level venous compression, with venous pooling of one or several nerve roots, would explain some of the pathophysiology of neurogenic claudication.Plain radiographs always show degenerative disease. They are essential to exclude other pathologies. The anatomical level of stenosis can not be determined from the history and examination alone. We have found that CT and MRI are satisfactory and can show central canal and lateral recess stenosis and nerve-root entrapment.Conservative treatment consists of anti-inflammatory analgesic drugs, back exercises, elastic back support and local injection (in the posterior joints or epidural space). Failure to respond to medical treatment necessitates surgical intervention.Surgical treatment consisted of a decompressive lumbar laminectomy of stenotic levels. The surgical technique consisted of standard midline spinal exposure, central decompression via removal of the spinous process and lamina staying medial to the articular facets and pars interarticularis, followed by appropriate lateral recess decompression, being careful to undercut the articular facets. The extent of decompression should be guided by the clinical features, the radiological studies and the operative findings.Our study included fifty patients with degenerative stenosis of the lumbar spinal canal. The fifty patients were divided into two equal groups, group A patients, were subjected to decompression by wide laminectomy technique and group B patients were subjected to decompression by wide laminectomy technique with spinal fusion with internal fixation.The mean age of group A patients was 55.5 years and 52 years in group B. The highest incidence lied in the 5th. decade of life. All the 23 females’ patients were heavy workers house wives living in the countryside and also all the males’ patients were engaged in occupations which demand heavy physical activity.The history reveals an insidious onset of low back pain which was present in 100% of our patients for a mean period of 17 months before surgery. Other symptoms consisted of leg pain, weakness and paraesthesia which may present as continuous or intermittent symptoms. Physical examination revealed the following abnormalities: positive straight-leg raising test in 56% of cases in group A, in group B the test was positive in 15 patients (60%). sensory hyposthesia found in 52% in group A and was found in 56% in group B. Reduced knee and ankle reflexes found in 44% of cases in group A and also in group B.All the patients were subjected to plain X-ray lumbosacral spine, 16% to CT scanning, 100% to MRI examination. Magnetic resonance imaging has rapidly become the imaging study of choice for the diagnosis of spinal stenosis and for the planning of the operation.The major indications for surgery were: intolerable pain in activities of daily living, in spite of adequate non-operative treatment; progressively limited walking distance and progressive neurological deficits. The surgical strategy was bases on the patient’s symptoms and roentgenographic findings. The commonest operative findings were narrowing of the central and the lateral canals. The number of disc prolapse revealed surgically was done to 5 patients (20%) in group A and was done to 6 patients (24%) in group B. One level laminectomy was not performed in our cases. Two-level laminectomy was performed in 32 cases and three-level laminectomy was performed in 16 cases where four-level laminectomy was performed in only 2 cases. The decision on how far cranial to proceed with decompression was dependant on the neurological examination, the roentgenographic and operative findings for every case.JOA scoring system was used for grading the outcome of surgery. Improvement after surgery was calculated at the final follow-up period (The mean duration was 24 months). The mean improvement rate was 61.37% in group A and 74.7% in group B. This means the total laminectomy with posterolateral fusion with internal fixation procedure give more satisfactory results (92%).We drew the following conclusions about the results of surgical treatment of degenerative lumbar spinal stenosis:• The history, rather than the objective findings, is the clue to reach a proper diagnosis.• Magnetic resonance imaging has rapidly become the imaging study of choice for the diagnosis of spinal stenosis and for the planning of the operation.• The extent of decompression should be tailored according to clinical, radiological and operative findings.• Exploration of the lateral recesses should never be missed during operation.• Unless a disc protrusion is compromising the nerve roots, the intervertebral disc should be left intact, its removal will increase the potential for spinal instability.• The facet joints should be preserved by using an undercutting technique in combination with laminectomy.• Wide decompressive laminectomy with posterolateral fusion with pedicular screw fixation gives better outcome than laminectomy alone in degenerative spinal canal stenosis.
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